#!/usr/bin/env python

import roslib
import rospy
import actionlib
from actionlib_msgs.msg import *
from geometry_msgs.msg import Pose, PoseWithCovarianceStamped, Point, Quaternion, Twist
from move_base_msgs.msg import MoveBaseAction, MoveBaseGoal
from random import sample
from math import pow, sqrt

class NavTest():
    def __init__(self):
        rospy.init_node('my_nav_test_1', anonymous=True)
        
        rospy.on_shutdown(self.shutdown)
        
        # How long in seconds should the robot pause at each location?
        # 在每个目标位置暂停的时间
        self.rest_time = rospy.get_param("~rest_time", 10)
        
        # Are we running in the fake simulator?
        # 是否仿真？
        self.fake_test = rospy.get_param("~fake_test", False)
        
        # Goal state return values
        # 到达目标的状态
        goal_states = ['PENDING', 'ACTIVE', 'PREEMPTED', 
                       'SUCCEEDED', 'ABORTED', 'REJECTED',
                       'PREEMPTING', 'RECALLING', 'RECALLED',
                       'LOST']
        
        # Set up the goal locations. Poses are defined in the map frame.  
        # An easy way to find the pose coordinates is to point-and-click
        # Nav Goals in RViz when running in the simulator.
        # Pose coordinates are then displayed in the terminal
        # that was used to launch RViz.
        # 设置目标点的位置
        # 如果想要获得某一点的坐标，在rviz中点击 2D Nav Goal 按键，然后单机地图中一点
        # 在终端中就会看到坐标信息
        locations = dict()
        
        # locations['hall_foyer'] = Pose(Point(0.643, 4.720, 0.000), Quaternion(0.000, 0.000, 0.223, 0.975))
        # locations['hall_kitchen'] = Pose(Point(-1.994, 4.382, 0.000), Quaternion(0.000, 0.000, -0.670, 0.743))
        # locations['hall_bedroom'] = Pose(Point(-3.719, 4.401, 0.000), Quaternion(0.000, 0.000, 0.733, 0.680))
        # locations['living_room_1'] = Pose(Point(0.720, 2.229, 0.000), Quaternion(0.000, 0.000, 0.786, 0.618))
        # locations['living_room_2'] = Pose(Point(1.471, 1.007, 0.000), Quaternion(0.000, 0.000, 0.480, 0.877))
        # locations['dining_room_1'] = Pose(Point(-0.861, -0.019, 0.000), Quaternion(0.000, 0.000, 0.892, -0.451))

        # locations['first'] = 

        # location['second'] = 

        # location['end'] = 



        
        # Publisher to manually control the robot (e.g. to stop it)
        # 发布控制机器人的消息
        self.cmd_vel_pub = rospy.Publisher('cmd_vel', Twist)
        
        # Subscribe to the move_base action server
        # 订阅move_base服务器的消息
        self.move_base = actionlib.SimpleActionClient("move_base", MoveBaseAction)
        
        rospy.loginfo("Waiting for move_base action server...")
        
        # Wait 60 seconds for the action server to become available
        # 60s等待时间限制
        self.move_base.wait_for_server(rospy.Duration(60))
        
        rospy.loginfo("Connected to move base server")
        
        # A variable to hold the initial pose of the robot to be set by 
        # the user in RViz
        # 保存机器人的在rviz中的初始位置
        initial_pose = PoseWithCovarianceStamped()
        
        # Variables to keep track of success rate, running time,
        # and distance traveled
        # 保存成功率、运行时间、和距离的变量
        n_locations = len(locations)
        n_goals = 0
        n_successes = 0
        i = n_locations
        distance_traveled = 0
        start_time = rospy.Time.now()
        running_time = 0
        location = ""
        last_location = ""
        
        # Get the initial pose from the user
        # 获取初始位置(仿真中可以不需要)
        rospy.loginfo("*** Click the 2D Pose Estimate button in RViz to set the robot's initial pose...")
        rospy.wait_for_message('initialpose', PoseWithCovarianceStamped)
        self.last_location = Pose()
        rospy.Subscriber('initialpose', PoseWithCovarianceStamped, self.update_initial_pose)
        
        # Make sure we have the initial pose
        # 确保有初始位置
        while initial_pose.header.stamp == "":
            rospy.sleep(1)
            
        rospy.loginfo("Starting navigation test")
        
        # Begin the main loop and run through a sequence of locations
        # 开始主循环，随机导航
        while not rospy.is_shutdown():
            # If we've gone through the current sequence,
            # start with a new random sequence
            # 如果已经走完了所有点，再重新开始排序
            if i == n_locations:
                i = 0
                sequence = sample(locations, n_locations)
                # Skip over first location if it is the same as
                # the last location
                # 如果最后一个点和第一个点相同，则跳过
                if sequence[0] == last_location:
                    i = 1
            
            # Get the next location in the current sequence
            # 在当前的排序中获取下一个目标点
            location = sequence[i]
                        
            # Keep track of the distance traveled.
            # Use updated initial pose if available.
            # 跟踪形式距离
            # 使用更新的初始位置
            if initial_pose.header.stamp == "":
                distance = sqrt(pow(locations[location].position.x - 
                                    locations[last_location].position.x, 2) +
                                pow(locations[location].position.y - 
                                    locations[last_location].position.y, 2))
            else:
                rospy.loginfo("Updating current pose.")
                distance = sqrt(pow(locations[location].position.x - 
                                    initial_pose.pose.pose.position.x, 2) +
                                pow(locations[location].position.y - 
                                    initial_pose.pose.pose.position.y, 2))
                initial_pose.header.stamp = ""
            
            # Store the last location for distance calculations
            # 存储上一次的位置，计算距离
            last_location = location
            
            # Increment the counters
            # 计数器加1
            i += 1
            n_goals += 1
        
            # Set up the next goal location
            # 设定下一个目标点
            self.goal = MoveBaseGoal()
            self.goal.target_pose.pose = locations[location]
            self.goal.target_pose.header.frame_id = 'map'
            self.goal.target_pose.header.stamp = rospy.Time.now()
            
            # Let the user know where the robot is going next
            # 让用户知道下一个位置
            rospy.loginfo("Going to: " + str(location))
            
            # Start the robot toward the next location
            # 向下一个位置进发
            self.move_base.send_goal(self.goal)
            
            # Allow 5 minutes to get there
            # 五分钟时间限制
            finished_within_time = self.move_base.wait_for_result(rospy.Duration(300)) 
            
            # Check for success or failure
            # 查看是否成功到达
            if not finished_within_time:
                self.move_base.cancel_goal()
                rospy.loginfo("Timed out achieving goal")
            else:
                state = self.move_base.get_state()
                if state == GoalStatus.SUCCEEDED:
                    rospy.loginfo("Goal succeeded!")
                    n_successes += 1
                    distance_traveled += distance
                    rospy.loginfo("State:" + str(state))
                else:
                  rospy.loginfo("Goal failed with error code: " + str(goal_states[state]))
            
            # How long have we been running?
            # 运行所用时间
            running_time = rospy.Time.now() - start_time
            running_time = running_time.secs / 60.0
            
            # Print a summary success/failure, distance traveled and time elapsed
            # 输出本次导航的所有信息
            rospy.loginfo("Success so far: " + str(n_successes) + "/" + 
                          str(n_goals) + " = " + 
                          str(100 * n_successes/n_goals) + "%")
            rospy.loginfo("Running time: " + str(trunc(running_time, 1)) + 
                          " min Distance: " + str(trunc(distance_traveled, 1)) + " m")
            rospy.sleep(self.rest_time)
            
    def update_initial_pose(self, initial_pose):
        self.initial_pose = initial_pose

    def shutdown(self):
        rospy.loginfo("Stopping the robot...")
        self.move_base.cancel_goal()
        rospy.sleep(2)
        self.cmd_vel_pub.publish(Twist())
        rospy.sleep(1)
      
def trunc(f, n):
    # Truncates/pads a float f to n decimal places without rounding
    slen = len('%.*f' % (n, f))
    return float(str(f)[:slen])

if __name__ == '__main__':
    try:
        NavTest()
        rospy.spin()
    except rospy.ROSInterruptException:
        rospy.loginfo("AMCL navigation test finished.")